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EQUINE > 18.3.1: Diagnostic methods and cycle manipulation in the mare > Flashcards

18.3.1: Diagnostic methods and cycle manipulation in the mare Flashcards

1
Q

True/false: a mare in the transitional period may stand to be bred/ appear to be in oestrus.

A

True

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2
Q

In late autumn, the mare’s cyclicity often ends with…

A

A silent or anovulatory heat

Some ponies cycle throughout the winter.

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3
Q

What are signs of the transitional period?

A
  • Mare may show oestrus behaviour
  • Mare may stand to be bred
  • Mare has follicles that grow and regress (not enough LH or LH-receptors) but these do not ovulate
  • Ovaries may be large with palpable follicles
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4
Q

The breeding season starts ~15th Feb so shortening the transitional period is necessary. How can this be achieved?

A
  • Providing 16hrs artificial light and additional nutrition from 1st Dec
  • (Some clinicians also administer GnRH at this time; efficacy unproven)
  • Once the mare is in the transitional period (follicles greater than 25mm in diameter) -> progestogens are administered to suppress the release of LH
  • This is in the form of altrenogest (Regumate) given in feed for ~10 days
  • Follicles grow during progestogen treatment
  • When follicles reach 45mm progestogen treatment is stopped and there is a release of LH which induces ovulation
  • (Some clinicians also give GnRH at this time to enhance the LH surge)
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5
Q

What 3 things can we used the manipulate the transitional phase?

A
  • Light
  • Progesterone/ progestogens
  • GnRH
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6
Q

What can we use to hasten ovulation in mares that are in oestrus?

A
  • GnRH
  • hCG (this is LH-like in activity)
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7
Q

When it the optimal mating time in mares?

A
  • Optimum mating = 24-48hrs before ovulation -> this means the sperm is in the tract waiting for the egg
  • Mares ovulate a secondary oocyte that is immediately fertilisable but remains viable for only 12hrs after ovulation
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8
Q

Signs of approaching ovulation on ultrasound

A
  • Follicle size (~40-50mm)
  • Follicle softening
  • Follicle wall thickened
  • Follicle haemorrhage
  • Follicle pointing
  • Reduction in uterine oedema
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9
Q

What can we use to induce return to oestrus when the mare is cycling but in the luteal phase?

A

Prostaglandin

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10
Q

Describe the characteristics of repro tract when the mare is in anoestrus

A

Anoestrus
* Ovaries: small and hard, with small follicles
* Uterus: flaccid
* Vagina: pale and dry
* Cervix: small and closed

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11
Q

Describe the characteristics of the repro tract when the mare is in the transitional phase

A

Transitional phase: irregular cycles, long oestrus
* Ovaries: larger - soft follicles that grow and regress
* Uterus: transitional
* Vagina: like anoestrus
* Cervix: like oestrus

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12
Q

Describe the characteristics of the repro tract when the mare is in oestrus

A

Oestrus
* Ovaries: medium with either follicle or corpus haemorrhagicum present
* Uterus: large and oedematous
* Vagina: moist and hyperaemic
* Cervix: broad and soft

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13
Q

Describe the characteristics of the repro tract when the mare is in dioestrus

A

Dioestrus
* Ovaries: medium sized, early CH feels like follicle. CL not palpable.
* Uterus: small and tonic
* Vagina: pale and dry
* Cervix: hard and narrow

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14
Q

Describe the characteristics of the repro tract when the mare is pregnant

A

Pregnant
* Ovaries: early on, these are medium-sized, but become very large when eCG is secreted
* Uterus: tonic and pregnancy swelling can be detected from 21 days
* Vagina: pale and dry
* Cervix: hard and narrow

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15
Q

What bacterial venereal pathogens do you screen for in the mare? What disease do these organisms cause?

A
  • Taylorella equigenitalis
  • Klebsiella pneumoniae
  • Pseudomonas aeruginosa

These organisms cause contagious equine metritis -> the mare does not get pregnant. They do not cause late abortion.

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16
Q

You have taken a clitoral sinus and clitoral fossa swab and want to test for Taylorella - what transport do you use and why? When must your sample reach the lab?

A
  • Taylorella is microaerophilic so has to be held at low oxygen -> transport in charcoal
  • Must arrive at lab promptly - do not swab on Friday or Saturday, do not want to get stuck in post
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17
Q

What should you do if CEM is isolated in mares prior to covering?

A
  • Isolate and treat infected mares
  • Notify owners of mares
18
Q

What should you do if CEM is isolated in stallions prior to covering?

A
  • Isolate and treat stallions
  • Notify owners of mares that covering may not be taking place as planned
19
Q

What should you do if CEM is isolated in mares and stallions after covering?

A
  • Cease covering
  • Check all mares implicated in the outbreak
  • Do not cover until 3 negative swabs each at least 2 days apart
20
Q

What viral venereal pathogens do we screen for in mares?

A
  • Ensure the mare is serologically negative to Equine Viral Arteritis (EVA)
21
Q

How is Equine Viral Arteritis transmitted?

A
  • Via respiratory tract route
  • Venereally including in chilled semen
22
Q

Clinical signs of Equine Viral Arteritis

A
  • Flu-like with significant conjunctivitis (pink eye), focal dermatitis, limb and ventral oedema
  • Pregnant mares may abort
  • Aborted foetuses appear partially autolysed (compared to fresh foetus in EHV) but still need appropriate pathological exam and testing
23
Q

Which animals can become persistently infected with Equine Viral Arteritis?

A
  • When stallions are infected with EVA, it can infected the accessory glands and result in persistent infection
  • Mares clear the infection within 1 month and develop immunity
24
Q

True/false: Equine Infectious Anaemia is notifiable.

A

True

25
Q

What non-venereal pathogens might we screen/ plan for in an animal coming to stud?

A
  • Equine herpes virus 1 -> plan vaccination for months 5, 7 and 9 of pregnancy
  • Equine herpes virus 3 (equine coital exanthema) - inspect and ensure negative
  • Equine infectious anaemia (EIA) -> ensure horses returning to the UK are serologically negative
  • Strangles - quarantine on entry to demonstrate no signs develop
26
Q

When would you take uterine swabs in the mare?

A
  • For bacterial venereal pathogen screening
  • In cases of endometritis
  • For endometrial bacteriology (in endometritis) to allow C&S
  • For the detection of other pathogens e.g. yeast, fungi
27
Q

When would you not expect to find bacteria in the uterus?

A
  • In the luteal phase - the cervix is closed so this would be significant if found
  • However uterine swabs are often taken during oestrus (HBLB guidance) when the cervix is open and you might find bacteria
28
Q

If a mare has a Category I endometrial biopsy, what does this mean for her estimated foaling rate? What about a Category III mare?

A

Endometrial biopsies
* Category I - no pathological changes and should have normal fertility; estimated foaling rate 80-90%
* Category III - severe endometrial changes; uterus may be incapable of supporting foetal development. Estimated foaling rate <10%

29
Q

What term is given to this phase?

A

Transitional phase

30
Q

What phase of her cycle is this mare in?

A

Oestrus

31
Q
A

Large volume of uterine fluid in a pyometra

32
Q
A

Typical appearance of a mare CL

33
Q
A

Abnormal CL with honeycomb appearance:
This is an anovulatory luteinised/ haemorrhagic follicle commonly seen at the end of the breeding season in older mares

34
Q

This mare has been barren for more than 2 seasons. She was served at a professional stud with appropriate veterinary management. She presents with fluid in her uterus shown below. What conclusions can you make about the likelihood of getting her pregnant?

A
  • This mare has long-term fluid accumulation in the uterus typical of chronic endometritis -> she has got chronic endometrial disease
  • She will have a poor prognosis for getting pregnant
  • She will have a poor prognosis for taking a foal to term
  • Attempting to manage this mare will cost a lot of money
35
Q

You are examining endometrial cytology from a mare. How many neutrophils is too many neutrophils to be normal?

A
36
Q

Indications for taking an endometrial biopsy

A
  • Barren mares
  • Repeat breeeder mares
  • Mares with early embryonic death or abortion
  • Anoestrus mares (during breeding season)
  • Mares requiring surgery of genital tract
  • Pyometra or mucometra
  • Fertility evaluation pre-purchase

Endometrial biopsies can inform you of the chances of a mare taking a foal to term.

37
Q

When can you take an endometrial biopsy?

A
  • Mid-dioestrus = good time as it minimises misleading histological changes
  • Biopsy can be taken at any time except pregnancy or when fibrosis of the cervix prevents it
38
Q
A

Normal endometrium

39
Q
A

Uterine adhesion

40
Q
A

Endometrial cyst

41
Q
A

This is Equine coital exathema
* Do not breed this mare until the lesions have resolved
* Check for lesions on the stallion’s penis
* Remember the mare may have been cleaned/ tail bandaged etc. by a member of staff with contaminated hands/ equipment

42
Q

What are the consequences of equine coital exathema?

A
  • Does not result in abortion or infertility
  • Stallion may be sore and unwilling to breed

EQUINE (59 decks)

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